Set Opera Mail as default app in Windows 10

I apologise at the outset if I'm raising a hoary issue. I can see from web searches others have had it - I haven't found an instance where anyone has solved it. I've tried to look in posts to this forum for an answer, but the search function doesn't help me, and I don't have time to scroll through 290+ pages. If a moderator can point me where to go, I'd be very grateful.

Just to confirm the issue: I have Opera Mail as my email app on a new (to me) Asus laptop. I am very happy with it in itself, but cannot find a way to set it as my default email app (so that I can right-click an item and raise a new email message, with whatever I've right-clicked as an attachment or inclusion).
I think the problem is essentially a Microsoft one, in that (a) Win 10 is poorly designed, or deliberately restrictive, as compared to all earlier Windows versions, in respect of setting default apps for file types and (b) this is compounded by their not including (? excluding) Opera Mail as an 'option' in the set default process that is offered.

Here's hoping there IS a solution or work round .....?
Sincerely
Ian Graham
Wales UK

Thank you for this.
I've attempted the re-install, but it didn't seem to offer me any options - as far as I could observe, it simply opened my existing installation. I have also downloaded the.zip file and opened it, and taken one look at the instructions. I'm not embarking on that at this time of night ! Will come back to it at an earlier stage of a day. But thanks again.

Thank you for this.
I've attempted the re-install, but it didn't seem to offer me any options

You can skip that. Just make sure that operamail.exe is at "C:\Program Files (x86)\Opera Mail\operamail.exe" and that operamail.exe (via the Opera Mail shortcut) is the one that you always run.

Once you've confirmed that, just right-click on "opera_m2_win64.reg" and choose merge. Then, "Opera Mail" will be available in "Default Programs" in the control panel in windows so that you can set Opera Mail as the default.

I appreciate your efforts, but it is simply not working for me as you describe. You're right about 'where' the exe is. I therefore uninstalled Opera Mail, and reinstalled it - but even without an installed version to 'update', I got no option screens whatever in the reinstall process, and therefore the reinstall is also in the wrong place.

Really, life is too short. I'm going to have a look at the apps my Win 10 does recognise. If any of them is serviceable, I'll go with it. I just don't like Mail 10.

I appreciate your efforts, but it is simply not working for me as you describe. You're right about 'where' the exe is. I therefore uninstalled Opera Mail, and reinstalled it - but even without an installed version to 'update', I got no option screens whatever in the reinstall process, and therefore the reinstall is also in the wrong place.